a. Field Of The Invention
This invention relates to a connector for inclusion in a sub-sea pipeline, for example, to thereby provide the same with a controlled weak point. More particularly, this invention relates to an apparatus which provides a controlled weak point which is relatively insensitive to line pressure.
B. Description Of The Prior Art
In installing and operating many sub-sea pipelines, it is often desirable to have a weak point therein at which place the line will part in response to a pre-determined tension load applied thereto. Certain places where it would be desirable to have such weak points might be at a place in the line where a branch line enters the main trunk line. By placing such a weak point in the branch line at the point adjacent to the trunk line, the branch line would be parted at a tension force level below that which would cause damage to the main trunk line. For example, such tension forces might be applied to a branch line by an underwater anchor being hooked thereon inadvertently. In normal application, if such a branch line were hooked and pulled excessively, the trunk line would likely be buckled or damaged in similar manner. By having a separable weak point placed next to the trunk line, the branch line would simply break away without damage to the trunk line.
Another point where it may be desirable to have a weak point in an underwater pipeline might be at the bottom of the riser pipe which is fastened to an offshore production platform. Occasionally, a pipeline will be pulled by an anchor being hooked onto it or by loads being exerted by storm conditions. If the pipeline at the bottom of the riser is not weakened by a weak joint, then the riser pipe might actually be pulled away from the platform, causing damage to the riser in the form of a buckle or rupture.